Th400 swap to Th200-4r?
08-17-2007, 12:26 PM
#1
Safety Car
Thread Starter
Th400 swap to Th200-4r?
Hi,
has anybody swapped out a th400 for a Th200-4r? Apparently a new yoke is needed, but does the stock Th400 driveshaft need to be modified? If it does, would it make sense to just use a yoke & driveshaft from a C3 running a th350?
TIA
has anybody swapped out a th400 for a Th200-4r? Apparently a new yoke is needed, but does the stock Th400 driveshaft need to be modified? If it does, would it make sense to just use a yoke & driveshaft from a C3 running a th350?
TIA
08-17-2007, 12:37 PM
#2
Le Mans Master
Yes, I believe you would need a TH350 driveshaft or modify the original. The yoke is the same as muncie 4-sp, TH350, or 700R4 for a C3. You need 1 with straps or u-bolts so it will go in without taking the car apart.
08-17-2007, 12:45 PM
#3
Le Mans Master
Member Since: Jan 2006
Location: Boca Raton Florida
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I am not sure you cna take the driveshaft out without taking the car apart!LOL
I'll look again, but it was a PITA when I took it apart
Mark is right about the driveshaft
I'll look again, but it was a PITA when I took it apart
Mark is right about the driveshaft
08-17-2007, 01:11 PM
#4
Safety Car
Thread Starter
Wow! Thanks for the quick replies 
The Th400 yoke, I've been told, has a different number of splines than a th200's, but when I fitted my Th200 the stock Th350 yoke slid right in & there were no driveshaft length problems. So it looks as if asking a local Vette specialist to supply a used yoke & driveshaft out of a Th350 equipped Vette would probably be the simplest/quickest solution?
Mark, good point, no straps or U bolts would make it a bit tricky to get in/out
Are U bolts stronger than straps on the UJ's, or are they about the same (this is going behind a big block)?
Is the driveshaft used in a BB stronger than that used in a SB, or are there any other potential "gotchas" with this swap that anybody can think of?
The Th400 yoke, I've been told, has a different number of splines than a th200's, but when I fitted my Th200 the stock Th350 yoke slid right in & there were no driveshaft length problems. So it looks as if asking a local Vette specialist to supply a used yoke & driveshaft out of a Th350 equipped Vette would probably be the simplest/quickest solution?Mark, good point, no straps or U bolts would make it a bit tricky to get in/out
Are U bolts stronger than straps on the UJ's, or are they about the same (this is going behind a big block)?Is the driveshaft used in a BB stronger than that used in a SB, or are there any other potential "gotchas" with this swap that anybody can think of?
08-17-2007, 01:44 PM
#6
Safety Car
The driveshaft you have will work without any changes. The front universal needs to be changed to the style that fits the new yoke. This is a self item at most parts stores.
200-4R repalced TH400 in my 73
200-4R repalced TH400 in my 73
08-17-2007, 03:48 PM
#7
Safety Car
When I did this swap, I re-used my driveshaft, and bought a new front yoke and combination u-joint.
While you have the driveshaft out, that's a great time to have it balanced
08-17-2007, 05:21 PM
#8
Melting Slicks
I just finished puting a 200R4 in my 80. Bow Tie Overdrives makes a nice crossmember to make the swap easie, it just bolts right up. I am using the yoke from the original th350c and the drive shaft.
08-20-2007, 06:02 AM
#9
Safety Car
Thread Starter
Thanks for the replies, they've cleared up some confusion 
It'll probably be a Level 3 BTO unit that gets put in there so (hopefully) the HP won't be a problem.
Dave, I've got one of those x-members in my '81. It's easy to fit a true dual system with it fitted
The reason I posted this question was because the current trans is a Th400 and, while I know the Th350 swap doesn't give any driveshaft/yoke issues, I didn't know if it was the same for a Th400.
It'll probably be a Level 3 BTO unit that gets put in there so (hopefully) the HP won't be a problem.Dave, I've got one of those x-members in my '81. It's easy to fit a true dual system with it fitted
The reason I posted this question was because the current trans is a Th400 and, while I know the Th350 swap doesn't give any driveshaft/yoke issues, I didn't know if it was the same for a Th400.
